1. The problem statement, all variables and given/known data An object gives out a spectral line of 919nm compared to that of 589nm in a laboratory. It has a brigtness of 1.2 x 10-11 W m-2. The objective is to find out the brightness of the object if it were at 700 Mpc. 2. Relevant equations 1. Z (redshift)= change in wavelength / original wavelength 2. V= Z X C 3. V= H0D 4. F= L / 4 pi r2 3. The attempt at a solution The redshift value I find to be 0.56 using equation 1. Using this I calculate the speed as 168000 km s-1 using equation 2. I then work out the distance of the object to be 2400Mpc using equation 3 rearranged. now from here do I use equation 4 to calculate the luminosity and then change the distance to 700Mpc or do I divide 2400Mpc by 700Mpc to get how many times closer the object will be square the answer ( 3.432) and times it by the original brightness 1.2 x 10-11 W m-2?